Allow partial update for notification update API

chrome/browser/notifications/notification_ui_manager.h

Index: chrome/browser/notifications/notification_ui_manager.h
diff --git a/chrome/browser/notifications/notification_ui_manager.h b/chrome/browser/notifications/notification_ui_manager.h
index 625793917a68a33c645d5b196e742acabf71f90d..a86f1d2308cb7f3fed0d2637acb318de97aa759f 100644
--- a/chrome/browser/notifications/notification_ui_manager.h
+++ b/chrome/browser/notifications/notification_ui_manager.h
@@ -29,9 +29,10 @@ class NotificationUIManager {
   virtual void Add(const Notification& notification,
                    Profile* profile) = 0;
 
-  // Returns true if any notifications match the supplied ID, either currently
-  // displayed or in the queue.
-  virtual bool DoesIdExist(const std::string& notification_id) = 0;
+  // Returns the pointer to a notification if it match the supplied ID, either
+  // currently displayed or in the queue.
+  virtual const Notification* FindById(
+      const std::string& notification_id) const = 0;
 
   // Removes any notifications matching the supplied ID, either currently
   // displayed or in the queue.  Returns true if anything was removed.